Phase shift mask including a substrate with recess

Abstract

A phase shift mask includes a quartz substrate having a main surface partially dug, and a Cr film deposited on the main surface. The dug portion includes an undercut provided such that the Cr film partially serves as an eaves, and the Cr film has a π opening exposing a portion of the dug portion, and a first subopening exposing an end of the dug portion.

1 - 16 . (canceled)  
     
     
         17 . 1. A method of fabricating a semiconductor device, comprising the steps of: 
 preparing a phase shift mask having 
 a shielding film formed on a main surface of a substrate,  
 a recess formed at a portion of said main surface of said substrate to allow said shielding film to have a portion serving as an eaves, and having an undercut,  
 a first main opening located in a region having said recess, formed in said shielding film to expose a portion of said recess, said first main opening being geometrically substantially similar to an end of said recess,  
 a second main opening formed in said shielding film to expose said main surface of said substrate, and  
 a subopening exposing a portion of said end of said recess having said first main opening; and  
   subjecting a semiconductor substrate to projection through said phase shift mask for exposure.    
     
     
         18 . A method of forming a phase shift mask, comprising the steps of: 
 preparing a phase shift mask having 
 a shielding film formed on a main surface of a substrate,  
 a recess formed at a portion of said main surface of said substrate to allow said shielding film to have a portion serving as an eaves, and having an undercut,  
 a first main opening located in a region having said recess, formed in said shielding film to expose a portion of said recess, said first main opening being geometrically substantially similar to an end of said recess,  
 a second main opening formed in said shielding film to expose said main surface of said substrate, and  
 a subopening exposing a portion of said end of said recess having said first main opening;  
   measuring an eaves in size through said first main opening and said subopening of said phase shift mask; and    performing one of dry etching and wet etching to vary said eaves in size to obtain a desired size